Field of the Invention
The present invention relates to a technique that provides a virtual space or mixed reality space.
Description of the Related Art
Recently, studies of MR (Mixed Reality) aiming at seamless combination of a physical space and virtual space have been made actively. An image display device which presents mixed reality is, for example, a device having the following arrangement. More specifically, this device displays an image obtained by superimposing and rendering, on an image in a physical space that is sensed by an image sensing device such as a video camera, an image in a virtual space (for example, a virtual object or character information rendered by computer graphics) that is generated in accordance with the position and orientation of the image sensing device. As such a device, for example, an HMD (Head Mounted Display) is usable.
The image display device can also be implemented by an optical see-through method that displays a virtual space image generated in accordance with the position and orientation of the viewpoint of an operator, on an optical see-through type display mounted on the head of the operator.
On the other hand, a virtual object is generally formed by using a commercially available CAD (Computer Aided Design) or 3DCG software (three-dimensional computer graphics software) (WORKS CORPORATION ed., “CG & Image Mechanism Encyclopedia”, issued Dec. 31, 2003, pp. 98-101). In addition, a method of providing an experience of a virtual reality space or mixed reality space by using the 3DCG software is also disclosed (Japanese Patent Laid-Open No. 2007-299062). By combining these techniques, an operator can experience a combination of the virtual reality space and mixed reality space by using the CAD and 3DCG software.
Unfortunately, the conventional methods have the following problem. That is, when an operator checks, in a mixed reality space, a virtual object which he or she has checked by CG software, the position of the virtual object is uncertain because the viewpoint at which the operator has checked the object last by the CG software is entirely different from the viewpoint of the mixed reality space.